Is there a risk in placing a ceramic head on a previously implanted trunion?

Abstract

Background: Strategies for revising a ceramic-on-ceramic total hip prosthesis are controversial. Some consider reimplantation of a ceramic head on a well-fixed femoral stem inadvisable as it may lead to a fracture of the newly implanted head.

Questions/purposes: We assessed (1) the risk of fracture when a new ceramic head was placed on a previously implanted trunion; (2) the survival rate of the revised hips; and (3) hip function and acetabular and femoral component loosening at midterm followup.

Patients and methods: We retrospectively reviewed all 126 patients (139 hips) who had revision of alumina-alumina hip arthroplasties between January 1977 and December 2005. Of these, 99 patients (110 hips) had revision of the socket only with retention of the femoral component. The femoral head was left in place in 33 hips, the same alumina head was re-implanted in seven hips, a new alumina head was implanted in 45 hips, a metallic head in 16, and a zirconia head in nine. Twenty-six patients (29 hips) died and nine (10 hips) were lost to followup before 5 years; this left 71 hips for review. Minimum followup was 60 months (mean, 112 months; range, 60-319 months).

Results: Eighteen hips required rerevision surgery, 11 for aseptic loosening, two for septic loosening, two for fracture of a ceramic liner, one for recurrent dislocation, one for ipsilateral femoral fracture, and one for unexplained pain. Among the 61 ceramic heads implanted on a well-fixed stem, no fracture of the head occurred at a mean 88 months' followup. The survival rate at 10 years with mechanical failure as the end point was 81.6%.

Conclusions: We observed no fractures of the ceramic heads implanted on a previous titanium trunion. This approach is possible if inspection shows no major imperfection of the Morse taper.

Fig. 1A–B

Actuarial survivorship curves show the survival rate at 10 years was (A) 81.6% (95% CI, 71.8%–91.4%) with mechanical failure as the end point and (B) 83.1% (95% CI, 73.6%–92.6%) with revision for mechanical failure as the end point.